Dont try it!!! Use a tremmie

You need to make your caisson less porous.

Or get bigger pumps.

More details needed.

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agree with miningman, tremie the concrete in. Essentially this is a pipe that you start at the bottom of your caisson and pump the concrete in under the water. As the concrete fills the caisson hole, it will push the water up.

ebooya,

I agree with miningman & Jayrod12, use a tremmie to place the concrete below the water surface.

As you place the concrete raise the bottom of the tremmie pipe (maybe a canvas tube) as the concrete is placed. Always keep the bottom of the tremmie tube below the top of the new concrete so there is a seal.

Any contractor who wants to bid on the job should be familiar with the concept.

Jim

It's tremie, not tremmie. And that is the method you have to use if you want sound concrete placement under water. Never heard of a canvas tube being used, but maybe...

The basics here:
https://en.wikipedia.org/wiki/Tremie

Thank you all for your feedback and your responses. I appreciate it.

Your are better off to dewater your cofferdams with submersible pumps before the concrete pours. The tremie pours we did were to seal up the bottom of the cofferdams before the concrete pours.

Quote (Your are better off to dewater your cofferdams)

I've done fully submerged coffer dams by tremie method...

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